freeCodeCamp/guide/english/css/dropdowns/index.md

title
Dropdowns

Dropdowns

Dropdowns are used in CSS to hide a predefined list within a button.

Examples:

<div class="dropdown">
  <button class="dropbtn">Name</button>
  <div class="dropdownContent">
    <a href="#">One</a>
    <a href="#">Two</a>
    <a href="#">Three</a>
  </div>
</div>

Then you should customise the classes in css

.dropdown {
  position: relative;
  display: inline-block;
}

.dropbtn {
  background-color: red;
  padding: 10px;
}

.dropdown-content {
  display: none;
  position: absolute;
}

.dropdown:hover .dropdown-content {
  display:block;
}

You need the separate div classes to create the button, and another div to separate the list of what the button contains.

An Example

<div id="container">

        <div id="myNav1" class="overlay">

            <div class="overlay-content" id="myNav1-content">

                <div>
                    <a href="#" id="list1_obj1" class="list1" >Content 1</a>
                </div>
                <div>
                    <a href="#" id="list1_obj2" class="list1" >Content 2</a>
                </div>

            </div>

         </div>

         <div id="myNav2" class="overlay">

             <a href="javascript:void(10)" class="closebtn" onclick="closeNav()">&times</a>
            <div class="overlay-content" id="myNav2-content">

                <div>
                    <a href="#" id="list2_obj1" class="list2" >Content 3</a>
                </div>
                <div>
                   <a href="#" id="list2_obj2" class="list2" >Content 4</a>
                </div>
                <div>
                  <a href="#" id="list2_obj3" class="list2" >Content 5</a>
                </div>

            </div>

         </div>

 </div>

#myNav1 {
  height: 0;
  width: 50%;
  position: fixed;
  z-index: 6;
  top: 0;
  left: 0;
  background-color: #ffff;
  overflow: hidden;
  transition: 0.3s;
  opacity: 0.85;
}

#myNav2 {
  height: 0;
  width: 50%;
  position: fixed;
  z-index: 6;
  bottom: 0;
  right: 0;
  background-color: #ffff;
  overflow: hidden;
  transition: 0.3s;
  opacity: 0.85;
}

.overlay-content {
  position: relative;
  width: 100%;
  text-align: center;
  margin-top: 30px;
}

#myNav1-content{
  top: 12%;
  left: 5%;
  display: none;
}

#myNav2-content{
  top: 12%;
  right: 10%;
  display: none;   
}

More Information:

• W3 School Dropdown Hover Button: Link to W3 School
• W3 School Dropdowns: Link to W3 School